In response to requests for higher speed, smaller size and the like in printing machines in recent years, resin binders for toner which can be fixed at lower temperature have been desired. In view of this, there have been reported a crystalline polyester prepared by using an aromatic carboxylic acid (JP-A-Showa-56-65146, JP-A-Hei-4-239021 and JP-A-Hei-8-36274), and a crystalline polyester prepared by using an aliphatic carboxylic acid (JP2001-222138 A, JP2002-287426 A and JP2003-173047 A).